Fatima León’s Extraordinary Margarita. Photo: Melissa Hom

Fifteen minutes into my meeting with the current star of the Mexican mixology scene, I have already committed a margarita mistake. Fatima León — who last year won the World Class Mexico, the country’s Olympics of mixology, cementing her place as the best bartender in the country — gives me a questioning look as I squeeze my lime into the margarita she’s just made.

“Should I not squeeze the lime into my drink?” I ask — even though I already know the answer.

“I don’t recommend squeezing them because the peel has a bitter flavor and it messes up the balance of the drink,” León tells me. She has briefly descended from her perch as the senior bartender at Fifty Mils, the cocktail bar at the Four Seasons in Mexico City, to come to the U.S., and teach me how to make the perfect version of what I might argue is the world’s most perfect drink.